Suggestions for failover/data-rate limiting

We currently have three BGP and MBGP peering sessions, one of which is
an Internet2 peer. Our primary peering session (peer A) is a 100 Mbps
connection. Our secondary connection (peer B) also is a 100 Mbps
connection rate-limited to 19 Mbps (for financial reason). The
Internet 2 connection (peer C) is a 100 Mbps connection.

Through various route maps, the Internet2 connection has the highest
priority. Should that peer go away, Internet2 traffic will then route
through peer B. All non-Internet2 traffic takes the path through peer
A except for traffic destined for ASs within peer B's network.

I have been asked to find a solution which does the following.

A. In the event of losing connectivity to peer A, bandwidth limit of
19 Mbps to peer B is automatically increased to 45 Mbps within 1
minute or less, and do this without any manual intervention (i.e.,
phone call to upstream to change the rate limit).

B. The design will need to be resilient to failure (hardware
redundant) or, in the case of failure, it should fail safely (do
nothing but function as a dumb, pass-through device).

All suggestions will be greatly appreciated.